CN100426541C - Light emitting device for generating visible light - Google Patents

Abstract

A light emitting device that produces visible light, comprising: a light emitting chip capable of emitting ultraviolet light and ultraviolet light with a wavelength of 250nm to 420 nm; an organic fluorescent layer, which is formed by vacuum evaporation, coating, screen printing, lithographic printing, sputtering, spot injection, casting, or adhering an organic polymer on the surface of the light-emitting chip; and a packaging layer containing a plurality of nano-scale crystal grains, wherein the luminous energy emitted by the luminous chip excites the organic fluorescent layer, the organic fluorescent layer can emit second light with the wavelength of 380 nm-800 nm after being excited, the second light and unabsorbed ultraviolet light are mixed in the packaging layer to form mixed light, the mixed light can be uniformly mixed after being condensed and refracted by the nano-scale crystal grains contained in the packaging layer, and then visible light with good uniformity, such as white light, red light, green light, blue light, yellow light, orange light, indigo light, purple light and the like, can be emitted outwards from the packaging layer.

Description

Light emitting device that produces visible light

technical field

The present invention relates to a light-emitting device, more particularly, the present invention relates to a light-emitting device that generates visible light, which is composed of red, yellow-green, and blue phosphors in different proportions excited by ultraviolet light-emitting diodes. Organic fluorescent layer, and by mixing light, it can produce visible light such as white light, red light, green light, blue light, yellow light, orange light, indigo light, or purple light with excellent uniformity and color rendering.

Background technique

There are many types of light-emitting diodes, which can be divided into two types: visible light-emitting diodes and invisible light (infrared light, ultraviolet light) light-emitting diodes according to the wavelength of light. Generally, visible light-emitting diodes are used in digital clocks, bank exchange rate billboards, traffic signs, outdoor information billboards, etc. Invisible light-emitting diodes are used in information and communication products, such as remote controllers, infrared wireless communication signal transmission, automatic doors, automatic flushing device control, etc. In recent years, the growth of the light-emitting diode market has been more obvious for visible light-emitting diodes (including white light-emitting diodes), especially for white light-emitting diodes. The scale of the invisible light-emitting diode market is relatively stable.

The light-emitting principle of light-emitting diodes is that when the bottom diode (usually a semiconductor material) is excited by electrical energy, electron and hole pairs are generated. When the electrons and holes are recombined, the diode emits the first emitted light (ultraviolet light or Blu-ray). The first emitted light can be absorbed by the phosphor and converted into the second emitted light (visible light wavelength range), when the first emitted light not absorbed by the phosphor is mixed with the second emitted light emitted by the phosphor , white light is obtained. With the combination of different fluorescent powders, the light emitting diodes can also have different light colors of cooler or warmer colors like fluorescent tubes.

At present, some light-emitting devices use ultraviolet light to excite inorganic phosphors to generate various colors of visible light, such as white light, red light, green light, blue light, yellow light, orange light, indigo light, and purple light. For example, US6555958 uses ultraviolet light to excite inorganic phosphors such as Ba ₂ SiO ₄ :Eu ²⁺ to produce blue-green light; US6501100 uses ultraviolet light to excite (Sr _0.8 Eu _0.1 Mn _0.1 ) ₂ P ₂ O ₇ Inorganic phosphors such as US6621211 use ultraviolet light to excite inorganic phosphors such as (Ba, Sr, Ca) ₂ SiO ₄ :Eu ²⁺ to produce white light; US6294800 uses ultraviolet light to excite Ca ₈ Mg ( SiO ₄ ) ₄ C1 ₂ : Eu2+, Mn ²⁺ and other inorganic phosphors to produce white light; US6616862 uses light waves from ultraviolet to blue light to excite (Ca, Sr, Ba, Mg) ₅ (PO ₄ ) ₃ :Eu ^{2 +} , Mn ²⁺ and other inorganic phosphors to produce yellow-orange light; US2003067265 uses ultraviolet light to excite A _2-2x Na _1+x E _x D ₂ V ₃ O ₁₂ (wherein A can be calcium, and E can be europium , D can be magnesium, x is 0.01 to 0.3) and other inorganic phosphors to produce white light; US2003067008 is produced by using ultraviolet light to excite inorganic phosphors such as (Sr _0.90-099 Eu _0.01-0.1 ) ₄ Al ₁₄ O ₂₅ White light; US2004007961 uses ultraviolet light to excite Sr ₂ P ₂ O ₇ :Eu ²⁺ , Mn ²⁺ and other inorganic phosphors to produce white light. However, the above-mentioned prior proposals all face problems such as weak reflection of the inorganic phosphors and poor luminous power of the device to be solved urgently. Therefore, how to develop a high-efficiency light-emitting device capable of generating visible light is the main subject of the present invention.

Contents of the invention

Therefore, the object of the present invention is to provide a light-emitting device that generates visible light, which is to excite the organic fluorescent layer composed of red, yellow-green, and blue phosphors in different proportions by violet and ultraviolet light-emitting diodes. The ultraviolet light not absorbed by the organic fluorescent layer and the second light emitted by the organic fluorescent layer are mixed with each other to produce high-power white light, red light, green light, blue light, yellow light, orange light, indigo light, or Visible light such as violet light, to solve the above-mentioned problems in the prior art.

In order to achieve the above object, the present invention provides a light-emitting device for generating visible light, comprising: a light-emitting chip, as a light-emitting source, which emits purple light and ultraviolet light with a wavelength between 250nm and 420nm; an organic fluorescent layer , the organic fluorescent layer is formed by forming an organic polymer on the surface of the light-emitting chip by vacuum evaporation, coating, screen printing, lithography, sputtering, dot casting, pouring, or bonding. and an encapsulation layer containing a plurality of nano-scale grains with a uniform diffusion function, the encapsulation layer encapsulating and encapsulating the light-emitting chip and the organic fluorescent layer, wherein the ultraviolet light emitted by the light-emitting chip The organic fluorescent layer can be excited, and the organic fluorescent layer emits a second light with a wavelength between 380nm and 800nm after being excited, and the second light is compatible with the ultraviolet light of the light emitting source that is not absorbed by the organic fluorescent layer. The light is mixed in the encapsulation layer to form a mixed light, which can be more uniformly mixed after being concentrated and refracted by the nano-scale crystal grains contained in the encapsulation layer, and then can be transmitted from the encapsulation layer to Visible light with good uniformity is emitted externally, and the organic fluorescent layer can be composed of organic phosphors such as red light, yellow-green light, and blue light in different proportions, so that the light-emitting device of the present invention can emit high-power white light and red light , green light, blue light, yellow light, orange light, indigo light, or violet light and other visible light, and the organic fluorescent layer material is the following organic polymer:

The first type: Melamine-Sulphonamide-Formaldehyde Copolymer Type (Melamine-Sulphonamide-Formaldehyde Copolymer Type);

Type II: Monoaminotriazine-Urea-Formaldehyde-Sulphonamide Cocondensate Type (Aminotriazine-Urea-Formaldehyde-Sulphonamide Type); or

The third type: 4,4-bis(2-dimethoxystyryl) biphenyl type (4,4'-Bis[2-(2-methoxyphenyl)etheny 1]-1,1'-diphenyl Type) .

The advantage of the light-emitting device of the present invention is that ultraviolet light excites the organic fluorescent layer composed of red light, yellow-green light, blue light and other phosphors in different proportions, and combines the ultraviolet light not absorbed by the organic fluorescent layer with the organic fluorescent layer. The light emitted by the fluorescent layer mixes with each other and is concentrated and refracted by the nano-scale crystal grains in the encapsulation layer to produce white light, red light, green light, and blue light with uniformity, excellent color rendering and stronger luminous intensity. , yellow light, orange light, indigo light, or violet light and other visible light to solve the problems of weak reflection of inorganic phosphors and poor luminous power of the device in the prior art.

From the following embodiments of the present invention and the accompanying drawings, the aforementioned and other objects, features, viewpoints and advantages of the present invention will be more clearly understood.

Description of drawings

Fig. 1 is a cross-sectional view of a light emitting device of the present invention;

Fig. 2 is a block diagram of the light-emitting process of the light-emitting device of the present invention; and

3 is a partially enlarged cross-sectional view of the encapsulation layer containing a plurality of nanoscale crystal grains in the light-emitting device of the present invention.

in the picture

10 light-emitting chips

12 luminous surfaces

15 light source

20 organic fluorescent layer

30 second light

35 mixed light

36 visible light

40 encapsulation layers

42 transparent resin

44 nanometer grain

Detailed ways

Preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

Fig. 1 is a cross-sectional view of a light emitting device of the present invention. As shown in FIG. 1 , the light-emitting chip 10 is used as a light-emitting source, and can emit light with a wavelength between 250nm and 420nm after being acted on by electrodes, that is, the light-emitting light source emits ultraviolet light. The organic fluorescent layer 20 is made of one of the following organic polymers (divided into the first type, the second type and the third type) are formed on the light emitting surface 12 of the light emitting chip 10, and the thickness of the organic fluorescent layer 20 can be determined according to the needs of the designer. The organic fluorescent layer material is the following organic polymer:

The first type: Melamine-Sulphonamide-Formaldehyde Copolymer Type (Melamine-Sulphonamide-Formaldehyde Copolymer Type);

Type II: Monoaminotriazine-Urea-Formaldehyde-Sulphonamide Cocondensate Type (Aminotriazine-Urea-Formaldehyde-Sulphonamide Type); or

The third type: 4,4-bis(2-dimethoxystyryl)biphenyl type (4,4'-Bis[2-(2-methoxyphenyl)etheny1]-1,1'-diphenyl Type).

The encapsulation layer 40 of the light emitting device is formed by uniformly mixing a transparent resin 42 and a plurality of nanoscale crystal grains 44 . The nano-scale crystal grains 44 are transparent or translucent, the size of which is controlled below 100 nanometers, and has the physical characteristics of concentrating and refracting light. The nanoscale crystal grains 44 are granular under a microscope, but powdery under human eyes. The light emitting device can emit various visible lights 36 with good uniformity and color rendering from the encapsulation layer 40 .

FIG. 2 is a block diagram of the light-emitting process of the light-emitting device of the present invention, and FIG. 3 is a partially enlarged cross-sectional view of the packaging layer containing a plurality of nano-scale crystal grains in the light-emitting device of the present invention. As shown in FIG. 2 and FIG. 3, when the light source 15 emits ultraviolet light with a wavelength of 254 nm to 420 nm, the ultraviolet light excites the organic fluorescent layer 20 so that the organic fluorescent layer emits a second light 30 different from the ultraviolet light, The wavelength of the second light 30 is between 380nm and 800nm, wherein the organic fluorescent layer 20 is formed by vacuum evaporation, coating, screen printing, lithography, sputtering, dot casting, casting, or The above-mentioned organic polymers (divided into the first type, the second type and the third type) are formed on the light emitting surface 12 of the light emitting chip 10 by bonding or other methods. Since the organic fluorescent layer 20 is formed on the light-emitting surface 12 of the light-emitting chip 10 after being cooled and shaped, its uniformity and adhesion are excellent, so that the luminous intensity and uniformity of luminous light can be improved. The layer can be composed of red light, yellow-green light, blue light and other organic phosphors with different proportions. Then the second light 30 is mixed with the ultraviolet light not absorbed by the organic fluorescent layer 20 to obtain a mixed light 35. When the mixed light 35 is projected on the transparent encapsulation layer 40, since there are several A large number of transparent nanoscale crystal grains 44 with the functions of concentrating and refracting light, so that the mixed light 35 is mixed, condensed, refracted and then emitted out of the transparent encapsulating layer 40 in the transparent encapsulating layer 40, so that a uniform Visible light 36 such as white light, red light, green light, blue light, yellow light, orange light, indigo light, or purple light with excellent color rendering and stronger luminous intensity, wherein the encapsulation layer 40 is made of transparent resin 42 and transparent or It is composed of translucent nano-scale grains 44 . The optimum mixing ratio of the material composition of the encapsulation layer 40 is 90% of the transparent resin 42 to 10% of the transparent or translucent nano-scale crystal grains 44 . The transparent or translucent nanoscale grains 44 are in various shapes, such as round, oval, polygonal, or irregular particles.

Various modifications and variations of the present invention will be apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, the present invention includes such modifications and changes, and they are all included in the scope of the appended claims and their equivalents.

Claims (5)

1. A light emitting device producing visible light, comprising: A light-emitting chip, as a light-emitting source, which emits purple light and ultraviolet light with a wavelength between 250nm and 420nm; An organic fluorescent layer, the organic fluorescent layer is an organic polymer formed on the luminescent layer by vacuum evaporation, coating, screen printing, lithographic printing, sputtering, point pouring, pouring, or bonding. made on the surface of the chip; and An encapsulation layer containing a plurality of nano-scale crystal grains with uniform diffusion function, the encapsulation layer encapsulating and encapsulating the light-emitting chip and the organic fluorescent layer, Wherein, the ultraviolet light emitted by the light-emitting chip can excite the organic fluorescent layer, and the organic fluorescent layer emits a second light with a wavelength different from that of the ultraviolet light after being excited, and the second light is the same as that without the organic fluorescent light. The ultraviolet light absorbed by the encapsulation layer is mixed in the encapsulation layer to form a mixed light, and the mixed light can be more uniformly mixed after being concentrated and refracted by the nano-scale crystal grains contained in the encapsulation layer, and then can be obtained from The encapsulation layer emits white light, red light, green light, blue light, yellow light, orange light, indigo light, or purple light with good uniformity and color rendering; Wherein, the organic polymer is: Type II: Monoaminotriazine-Urea-Formaldehyde-Sulphonamide Cocondensate Type (Aminotriazine-Urea-Formaldehyde-Sulphonamide Type); or The third type: 4,4-bis(2-dimethoxystyryl)biphenyl type (4,4'-Bis[2-(2-methoxyphenyl)etheny1]-1,1'-diphenyl Type). 2. The light-emitting device for generating visible light as claimed in claim 1, wherein the encapsulation layer is formed by mixing a transparent resin and the nanoscale crystal grains. 3. The light-emitting device for generating visible light as claimed in claim 1 or 2, wherein these nano-scale crystal grains are transparent or translucent, the particle size is controlled below 100 nanometers, and has the physical properties of concentrating and refracting light. characteristic. 4. The light-emitting device for generating visible light as claimed in claim 1, wherein the wavelength of the second light is between 380nm˜800nm. 5. The light-emitting device for generating visible light as claimed in claim 1, wherein the organic fluorescent layer is composed of red light, yellow-green light, and blue light organic phosphors in different proportions.

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